The next () function in Python

 random = [5, 9, 'cat'] # chuyển list thành iterator randomIterator = iter(random) print(randomIterator) # Output: 5 print(next(randomIterator)) # Output: 9 print(next(randomIterator)) # Output: 'cat' print(next(randomIterator)) # Xảy ra lỗi # iterator hết print(next(randomIterator)) 

When you run the program, the output will be:

  5 9 cat Traceback (most recent call last): File "python", line 18, in StopIteration 

In the above code, the list is an iterable object, and you can get the iterator from there using the built-in function iter () in Python.

Read more: Iterator object in Python

The above example encountered the StopIteration exception in the last command because the next () function returned the last value above, no more elements. In this case, you should include a default value of the second parameter so that no error occurs.

Example 2: Iterator has the default value in next ()

 random = [5, 9] # chuyển list thành iterator randomIterator = iter(random) # Output: 5 print(next(randomIterator, '-1')) # Output: 9 print(next(randomIterator, '-1')) # randomIterator đã hết phần tử # Output: '-1' print(next(randomIterator, '-1')) print(next(randomIterator, '-1')) print(next(randomIterator, '-1')) 

Return value:

 5 9 -1 -1 -1